Towing in overdrive

[dcs02d]

I've got an old crapbox Mazda MPV minivan with 130K miles on it.

I'm towing a loaded up scamp 13 so I'm probably pulling about 1400lbs,

Tinkering with different tow speeds I've found if I run just under 60MPH I can stay in overdrive mode... the RPMs stay below 2000 and my fuel economy pushes 20mpg.

If I speed up a little or turn the over drive off my fuel economy drops to about 13mpg. Yikes!

I'm in Florida so it's mostly pretty flat. Is it a problem to tow with the overdrive on? I try to stay off the interstate as I go slow and 60MPH on I75 feels suicidal.

I don't really care that much about the van... it was a 5K van when I bought it and I plan to keep driving it until it dies.

But I don't want to just ruin the transmission in the next 6 months either.

Thanks...

[gordon2]

Check the owners manual. If manual does not give instructions on how to tow, then call Mazda tech support at their corporate headquarters (you can ask them, but don't trust the local dealer or service manager to know anything). Don't forget that air resistance has a major effect also at highway speeds.

FYI, I tried towing a 2450 lbs Scamp with a Toyota van (3500 lb towing rating) with overdrive on vs overdrive off in the flats of Iowa while monitoring transmission temps. Even though the tranny did not shift at constant 55-60 MPH on level roads, the tyranny ran noticeably hotter with overdrive ON (possibly shortening the life of the transmission, esp if the fluid was not changed in time). Mileage did increase but no more than one MPG. YMMV.

[C&G in FL]

As to the comment that 60 mph on I-75 feels suicidal, I truly feel your pain. But I don’t think this is restricted to I-75; it seems common on most if not all Interstate highways. It seems most drivers just cannot stand to be behind someone towing a trailer. I do not allow other drivers to dictate the speed at which I tow. The majority of them are exceeding the speed limits in the first place. I just drive at 60 to 65 when towing, staying in the far right lane when possible. Doing so eliminates the annoyance of people passing on both sides, which adds to the “suicidal” feeling, at least for me.

[k0wtz]

don I have a 13f scamper I have done everything I can to reduce my weight I took the extra tank off, no water no more pots and pans than we need, not much food there are stores.

saying that I run our ford edge 2.0 at 55 we are not in a race you know by the way most trailer tires rated 60 so speed at your own risk. I run o/d I watch for hills and paddle shift to 5th gear.

I tried running 5th all the time hard on gas milage i don't think i am hurting my transmission doing this. trailering is a different animal!

good luck

bob

[Kenton]

You might consider picking up a Scanguage or Ultraguage if they will display the transmission temperature for your vehicle if it does not display it. Most vehicles made in the last 10 or so years will work, older ones too, you just need to contact the companies or check enthusiast websites. We own a 2013 Tacoma and pan, torque converter temperatures and torque converter lock up can be displayed. In Florida towing at 60/65 mph with no head wind it can be left it in overdrive and the torque converter stays locked and the temperature stays below 180F. A head wind and the temperature often starts climbing so it's dropped back to 4th. On ours there is a warning light for transmission temperature but it goes off at 302F. By then the transmission could be damaged. Coming back from Chilliwack when we picked up the trailer we experienced temperatures in the 230F range a few times climbing so I added an additional transmission cooler to the vehicle. It seemed to help as I have not gone over 210F since and we have been up in the Georgia, Tennessee and North Carolina mountains with no problems. That beats pulling to the side and waiting for the transmission to cool down.

Edit, we tow around 60/65 most of the time. I can go faster but the average MPG drops quickly from 13.6 /14.5 MPG when I do so. I'm retired, not in a hurry and in the slow lanes while traveling.

[k0wtz]

carl my driving style as well it seems drivers have trouble staying focused on driving. you know the guy who comes flying up behind you and tailgates and really in his mind wants you off the highway. sort of like bullying!


I cannot justify in my mind driving any faster for any reason with a rocket tied behind me. almost every trailer tire is rated for 60mph so why chance a blowout at 75mph. I don't get it but my neighbor does this with his 5th wheel I just shake my head there is no use saying anything but if I am on vacation what is the rush?

[Kenton]

Originally Posted by k0wtz

carl my driving style as well it seems drivers have trouble staying focused on driving. you know the guy who comes flying up behind you and tailgates and really in his mind wants you off the highway. sort of like bullying!


I cannot justify in my mind driving any faster for any reason with a rocket tied behind me. almost every trailer tire is rated for 60mph so why chance a blowout at 75mph. I don't get it but my neighbor does this with his 5th wheel I just shake my head there is no use saying anything but if I am on vacation what is the rush?

A lot of the newer ones are rated higher. Ours are rated 81 MPH but no way I'm going that fast! Not only is it unsafe the gas gauge needle would be visibly dropping. I do speed up in certain areas. Going through Atlanta area for instance.

[k0wtz]

Kenton st Louis comes to mind here

bob

[Alex Adams]

Originally Posted by k0wtz

carl my driving style as well it seems drivers have trouble staying focused on driving. you know the guy who comes flying up behind you and tailgates and really in his mind wants you off the highway. sort of like bullying!


I cannot justify in my mind driving any faster for any reason with a rocket tied behind me. almost every trailer tire is rated for 60mph so why chance a blowout at 75mph. I don't get it but my neighbor does this with his 5th wheel I just shake my head there is no use saying anything but if I am on vacation what is the rush?

That is why I prefer to take the back roads and avoid the Interstates wherever possible. I think the journey is as important as the destination and plan my trips accordingly. Besides, you miss a lot of interesting stuff when you take the Interstates.

[k0wtz]

alex you are right I notice then the race cars are out of your hair! I am the old guy running down the highway with those funny looking sun glasses by the way!!




bob

[floyd]

Check to see if your torque converter locks in any gear other than overdrive.
Pay attention to whether the transmission is down shifting a lot.
You can downshift when approaching a long grade to avoid automatic shifting half way up.


As for 60MPH towing, we have towed at or about 60MPH on just about every interstate in the country. No more problems than driving the Mustang at 80MPH. In fact probably less trouble with tailgaters!
Now if I drove the Mustang at 60MPH I would hear a lot of honking and screeching brakes along with some sign language.
With the Scamp, other drivers see it and anticipate passing as they approach. I see a lot of thumbs up but no middle fingers yet.
Speed limits are 65 to 70 around the country, average speed is about 75.
Minimums are usually 45.
I still pass occasionally but not often, but that is where the problem lies.
DO NOT pull out to pass at 60MPH in traffic with some cars exceeding 80 without waiting for a lot more clearance than normal.

Towing a trailer at ten MPH under the average traffic speed requires a different technique than driving a car ten miles over the average traffic speed. Either can be done safely but the former is a lot easier and legal.
That leaves driving AT the average speed, if you want tailgaters and threats, do that in the left lane!

[mchalewj]

I towed my Perris Pacer with a 1989 Mercury Sable wagon--in overdrive! I did install the biggest motorhome transmission cooler I could fit in front of the A/C condenser. Never had a problem. The car had between 100,000 and 200,000 miles when it towed the trailer every summer to Glacier and Yellowstone National Parks from the Yakima Valley. As long as the torque converter remained locked-up (engine RPM at 2,000), I left it in overdrive. I did shift down to "D" (third) to climb a steep grade. Again, no transmission troubles ever. Keep that fluid cool and your transmission will last. Please note that the transmissions in the Taurus and Sable are famous for failure. Ford rates towing capacity at "NOT RECOMMENDED" for these cars.

[floyd]

Originally Posted by Alex Adams

That is why I prefer to take the back roads and avoid the Interstates wherever possible. I think the journey is as important as the destination and plan my trips accordingly. Besides, you miss a lot of interesting stuff when you take the Interstates.

Driving on two lane roads with a crossroad every mile, stop signs, small town traffic (with pizza delivery), pedestrians, driveways, etc, is certainly less safe and harder on equipment than driving on the Interstate.
Taking the "scenic route" and watching the scenery instead of the road can compound the problem.
BTW... the difference in speed is a LOT wider (0-75MPH). Interstates have paved shoulders instead of two feet of gravel and a ditch!

All that being said, good defensive driving can make driving much safer than mowing the lawn or a walk around the block.
Driving America's back roads can be a wonderful experience as long as that "interesting stuff" doesn't take your mind off your driving too much.

[Nor Cal Mike]

An attuned driver can tell if he or she is over taxing the engine or transmission by running in a higher gear than is prudent. If you have an automatic trans is it on the verge of shifting all of the time? Do you check the trans fluid regularly for evidence of overheating? If you have a standard trans, do you hear feel or sense any additional vibration or noises under load? A mechanically intuitive driver can sense these things through their feet on the accelerator pedal, through seat of their pants or the vibrations in their ears. I don't know if it can be taught. When in doubt, I would rather burn a little more gas by downshifting for a spell rather than risking my transmission.

[TappyGee]

Originally Posted by CPW

...I do not allow other drivers to dictate the speed at which I tow. The majority of them are exceeding the speed limits in the first place. I just drive at 60 to 65 when towing, staying in the far right lane when possible...

Agree 100%.

[Wayne Collins]

Originally Posted by dcs02d

I've got an old crapbox Mazda MPV minivan with 130K miles on it.
……………..
But I don't want to just ruin the transmission in the next 6 months either.

Thanks...

Depends on your TV. But in general you're OK to tow in OD on level or downhill roads. I assume it's an automatic. If you have a transmission temp gauge, you're ahead of the game.
Most cars have the transmission oil cooler coils inside the bottom tank of the radiator, therefore the coolant temp gauge will give you an indication of transmission temperature. As another said, downshift on the upgrades to keep the torque converter from slipping too much; as that is what causes the oil to get hot.

[floyd]

Originally Posted by mchalewj

I towed my Perris Pacer with a 1989 Mercury Sable wagon--in overdrive! I did install the biggest motorhome transmission cooler I could fit in front of the A/C condenser. Never had a problem. The car had between 100,000 and 200,000 miles when it towed the trailer every summer to Glacier and Yellowstone National Parks from the Yakima Valley. As long as the torque converter remained locked-up (engine RPM at 2,000), I left it in overdrive. I did shift down to "D" (third) to climb a steep grade. Again, no transmission troubles ever. Keep that fluid cool and your transmission will last. Please note that the transmissions in the Taurus and Sable are famous for failure. Ford rates towing capacity at "NOT RECOMMENDED" for these cars.

The problem with the Taurus transmission was fluid routing. It effected only early cars.
Later models (don't recall the year) were changed to solve the problem.
Kits were also sold to retrofit the early cars.

Even hard driving could burn up the early transmissions without the reroute. Towing more than a light, open utility trailer would do it.
My FIL drove his without the fix for 130000 miles without trouble, then he gave the car to a grandchild...

[rbryan]

Originally Posted by Alex Adams

That is why I prefer to take the back roads and avoid the Interstates wherever possible. I think the journey is as important as the destination and plan my trips accordingly. Besides, you miss a lot of interesting stuff when you take the Interstates.

Amen to this. Provided we don't have a tight timeline (which we try to avoid also) we take state highways or rural roads almost exclusively. You see so much more, there are more interesting places to stop, and it makes the trip part of the experience and not just the destination.

[Kenton]

Originally Posted by Nor Cal Mike

An attuned driver can tell if he or she is over taxing the engine or transmission by running in a higher gear than is prudent. If you have an automatic trans is it on the verge of shifting all of the time? Do you check the trans fluid regularly for evidence of overheating? If you have a standard trans, do you hear feel or sense any additional vibration or noises under load? A mechanically intuitive driver can sense these things through their feet on the accelerator pedal, through seat of their pants or the vibrations in their ears. I don't know if it can be taught. When in doubt, I would rather burn a little more gas by downshifting for a spell rather than risking my transmission.

Unfortunately more and more manufactures are taking the ability to easily check transmission fluid out of the equation. Ford F150's Toyota Tacomas and I'm not sure which others no longer have dipsticks.

And you really can't listen to the engine or know when the torque converter is not locked unless you stare at the RPM gauge. Which is as bad as texting since you are not paying attention to the road. Most modern vehicles are drive by wire, have lots of soundproofing and and have done as much as possible to disconnect the power train from the cab so they can advertise how smooth and quiet they are.

Instead of trying to listen to the engine I added an Ultraguage which gives me transmission pan temperature, torque converter temperature, is the torque converter locked or not, engine temp, oil temp and battery voltage. I could have more but that's all the ones I care about. A quick look tells me if anything is amiss.

Edit F150's and others have added fake engine noise so you hear the engine growling inside the cab. And yes they actually do that. It's common now .

[Raspy]

Don,

If you can limit it to certain gears and watch the instantaneous mileage readout, you can tell if the different gears cause lower mileage. I suspect that dropping out of OD at 60 MPH is not the real mileage killer as the engine can breathe its best, typically, at speeds above 2000 RPM. Also, it's very unlikely that they would have programmed that vehicle to allow it to hurt itself. If it needs to downshift, it will. You don't say what year your van is, but manufacturers used to lean engines way out below 2500 RPM to pass emissions testing and they were gutless. Above that point they ran much better. As far as the tranny is concerned, if it is in lockup when towing, you are not making extra heat to worry about. The real heat source is the slipping torque converter, but that is not happening when locked. Make sure it's locked when towing. This is more likely to be the case when the RPM is a bit higher, or not in OD at near full throttle.

Lugging along where you have no throttle response in OD when towing, is less fun. The engine can be below it's best torque RPM and driving is more tiresome. You can't pull any hills, or headwinds, or do any passing as the engine is maxed out at that speed.

My old Dodge Dakota was that way. I could pretty much keep it floored in 5th all day and the mileage was terrible. But a downshift gave me more power and better mileage.

My Jeep gets to full torque above 2100 RPM, so I run it just over that. It gets good mileage there and has power to pull hills.

My Cummins is interesting, it gets to full design torque at 1400 RPM, but wants to tow above 1800 RPM. Towing heavy in 6th gives poor throttle response but no better mileage than towing in 5th. It's doing the same amount of work at 60 MPH whichever gear you're in, so try to make the engine run efficiently.

Speed has an exponential affect on mileage. Slightly faster causes much more drag. So if mileage is the main concern, keep the speed down.